In U.S. Pat. No. 3,671,542, it is disclosed that high strength, high modulus fibers can be obtained by the spinning of concentrated solutions of rigid chain, rod-like polyamides. The molecular geometry of the polymers must be such as to define a straight line chain conformation, thereby generating anistropic, liquid crystalline solutions. The success or failure of obtaining such solutions is to a large degree dependent on the variety of solvents which can be used as well as temperature, percent concentration, molecular weight, and molecular weight distribution. As disclosed in the aforementioned patent, strong acids are used as solvents, which is a disadvantage from a processing standpoint. Also, the polyamides are hydrolytically unstable, a condition which renders the polymers unsuitable for many applications.
It is a principal object of this invention, therefore, to provide p-terphenylene-dicarboxylic acid monomers which can be used in the preparation of hydrolytically and thermally stable rod-like polymers.
Another object of the invention is to provide monomeric materials containing pendant aromatic groups which prevent the close packing of chains when the materials are polymerized, thereby reducing the high degree of intramolecular association and, as a result improving solubility parameters.
A further object of the invention is to provide a process for synthesizing the p-terphenylene-dicarboxylic acid monomers.
Other objects and advantages of the invention will become apparent to those skilled in the art upon consideration of the accompanying disclosure.